All language subtitles for 004 What To Test & How To Test_en

Now, when you start writing tests,

there are two super important questions

you have to answer, relatively early.

And, these questions are

what you should test,

and how you should test that.

And, I don't mean how you should technically test that.

So, how you make sure that you have some code

that is then executed by some other tool.

I'll come back to that technical question later,

but I mean, which kind of code

should you put into your testing code?

Now, when it comes to what to test,

then, as mentioned for unit tests,

you wanna test the different building blocks

that make up your application,

and you really wanna test

small building blocks,

so that you have small, focused tests,

that only test one main thing each.

So, that you really have a lot of focused tests,

which then also fail for a clear reason,

if they do fail,

instead of having a few large tests,

which could fail for all kinds of reasons.

Now regarding the "how",

you wanna test success and error cases,

that could occur,

if a user interacts with your application.

And, you also, of course,

wanna test some rare,

but possible scenarios and results.

And again, that will become a bit clearer,

once we start writing some code.